One of the most anticipated cases of the Supreme Court’s 2014-2015 term is King v. Burwell. In it, the Supreme Court is confronted with what should be a straightforward question of statutory interpretation about the scope of subsidies available under the Affordable Care Act (ACA). Section 1311 of the ACA states that “each state shall, not later than January 1, 2014, establish an American Health Benefit Exchange.” Another part of the law, section 1321, then qualifies that apparently absolute duty by providing that if the state does not “elect” to establish that exchange by January 1, 2014, or if it otherwise fails to meet the federal requirements for an exchange, “the Secretary [of HHS] shall . . . establish and operate such exchange within the state.”

The question of whether a state establishes this exchange determines far more than where individuals can buy their health care coverage. It also determines whether any purchaser of health insurance is entitled to a tax credit against his or her cost of coverage, as that subsidy is limited to taxpayers who are enrolled in a qualifying plan “through an Exchange established by the state” under Section 1311. Internal Revenue Service regulations interpreted the ACA requirement so that its tax subsidies were available to all individuals whether they enrolled in an exchange established by the state or by HHS when the state elected or failed to do so. The plaintiffs’ challenge to the regulation was in essence that the plain language of the ACA precluded the IRS from expanding the scope of the subsidy by this sleight of hand. King would have been an open-and-shut victory for the plaintiffs if the disputed interpretation had been some run-of-the-mill tax provision. But 36 states did not establish these exchanges because they wanted to guarantee their citizens the statutory tax breaks.